Multifunctional snail mucus comes in five different types of mucus

Amazing stuff!

"... One of the world’s most impressive multi-purpose tools just might be snail mucus—that slimy secretion that leaves glistening trails across gardens. The brown-lipped snail, native to central Europe, is a true jack-of-all-slimes. This gifted gastropod produces multiple types of mucus with different properties, from the slippery mucus that helps the snail move to a foamy, defensive slime thought to deter predators.

How do these snails do it? To find out, scientists ... spent rainy days collecting snails they found on campus. Once in the lab, the team examined the various types of mucus the critters produced.

They found that, while all the slimes used collagen as a main ingredient, the concentration of that collagen varied, with calcium and other ions also determining each slime’s unique properties .

More collagen and calcium, for example, gives rise to the stiffer, stickier mucus that helps snails cling to surfaces,

while tiny calcite crystals harden the protective mucus the animals use to seal themselves inside their shells during hibernation. ..."

"To the point:

• An ordinary organism: The slime of the garden snail (Cepaea nemoralis) is a multifunctional biomaterial, as it can be extremely sticky or extremely slippery depending on its function. The garden snail is the most common snail species in Europe and can also be found on the Max Planck Campus in Potsdam-Golm.
• A molecular building block system: The snail uses the same molecular building blocks to produce different types of mucus. It varies the exact composition depending on whether it uses the mucus for locomotion, adhesion, protection, or defense.
• Bio-inspired: The discovery could advance the development of environmentally friendly adhesives, functional coatings, and medical materials.

..."

From the editor's summary and abstract:

"Editor’s summary

Organisms can fabricate materials with completely different mechanical properties using a limited number of building blocks, such as the way that

spiders can spin multiple types of fibers for different parts of their webs.

Gabler et al. studied the composition and structure of different mucus-based materials produced by the terrestrial snail Cepaea nemoralis. They found that the different types of mucus share many similar protein constituents and that collagen VI is a main structural component. Amorphous calcium carbonate is added into the different materials, where it can function as an ion source, a stabilizing component, or a mineral precursor depending on the mucus type. ...

Abstract

Mucus is known as a viscous fluid; yet, snails manufacture various mucus-based materials with much higher cohesion and tailored to different and even antagonistic functions, including lubrication, adhesion, protection, and defense. To gain insight into this versatility, we use a multidisciplinary approach to investigate five different mucus-based materials produced by the snail Cepaea nemoralis.

Our results demonstrate that snails use collagen VI as a main structural component and add amorphous calcium carbonate (ACC) during mucus secretion.

ACC functions as an ion source in wet mucus types, most likely for cross-linking, or as a mineral precursor in dry mucus types. These findings shed light on the versatility of these viscoelastic materials, which are able to switch between very different properties on the basis of calcium and protein content."

ScienceAdviser

Following the Trail of Slime (original news release) "Snails can adjust the chemical composition of their mucus to make it liquid, solid or sticky as needed."

Calcium tunes snail mucus–based materials to multiple functions (no public access)

Calcium tunes snail mucus-based materials to multiple functions (preprint, open access)

Shrinking squid brains due to climate change. Really!

Caution: Again junk science disseminated by the AAAS!

Reminder: Climate models are largely junk! We can not even forecast local weather accurately for more than 48 hours!

"... Squid are some of the ocean’s most intelligent inhabitants. Capable of clever problem solving, advanced communication, and learning from past experiences, these squishy swimmers’ brains contain a similar number of neurons as dogs. But now, thanks to climate change [???], those impressive brains may be doomed to downsizing.

At the Society of Experimental Biology conference held this month in Florence, Italy, scientists presented early data from a study of bigfin reef squid. They raised the animals for 90 days in one of two water tanks: one with a pH of 8.2, similar to modern oceans, and one with a pH of 7.8, which is the value oceans could reach by the year 2100 [???] under continued climate change. As carbon dioxide levels rise in the atmosphere, nearly one-third gets absorbed into the ocean, causing the water to become more acidic.

After analyzing the squids’ heads with magnetic resonance imaging, the researchers made a shocking discovery: The brain volume of squid raised in more acidic tanks was half as large as their counterparts.

Further analysis revealed that the squids’ brain volume had shrunk the most in regions responsible for visual processing. Since bigfin reef squid rely on their eyes to hunt, the findings help explain a previous observation that this species, when exposed to high carbon dioxide levels for 90 days, showed a 42% reduction in hunting behaviors. ..."

ScienceAdviser

Squid Are Among the Most Intelligent Ocean Creatures. Climate Change Might Shrink Their Brains

Ocean acidification may be shrinking the brains of the world’s most intelligent invertebrates

Double-headed at opposite ends microscopic flatworms in the wild

Amazing stuff! Wish you could split your body in half sometimes? Maybe this is more than a curiosity!

"... Stenostomum brevipharyngium? This microscopic flatworm reproduces asexually by splitting its body in half, with each new worm regenerating either a new head or a new tail. But this process, known as parotomy, doesn’t always go as planned—sometimes resulting in offspring with heads at both ends.

Surprisingly, these bizarre-looking critters don’t seem to mind. When scientists looked more closely at the worms’ brains, they found that, while some structures were a bit topsy-turvy, they didn’t appear to be malformed—suggesting that the erroneously grown heads are fully functional. The defect also isn’t heritable, so a double-headed individual can go splitsies to produce perfectly normal offspring. Chopping the mutant worms up into pieces revealed that a fragment with a misplaced head can even grow a new tail at what was once its front end, creating a healthy animal with its head and tail positions permanently swapped. ..."

From the abstract:

"In most of the animals, the antero-posterior axis is specified during early embryogenesis. However, in the organisms that undergo somatic asexual reproduction, constant re-establishment of the body axis occurs during each asexual act in the context of the fully formed adult body.

In microscopic flatworms from the genus Stenostomum the new head and tail structures are inserted in the pre-existing body plan during the asexual process known as paratomy.

Here, we report a spontaneously occurring developmental error that results in the formation of worms with double heads at opposite ends of their bodies, lacking posterior pole identity. In the set of experiments, we show that the double-head phenotype is not heritable on the organismal level.

Worms originating from the sectioning or fission of the double-head animals give rise to the healthy populations that do not display the erroneous asexual development.

We also demonstrate that the piece of the worm with ectopic head can survive, regenerate the tail on its previously anterior pole and resume asexual reproduction.

Effectively, such regeneration allows stable reversal of the body axis polarity without impairment of the survival or reproductive abilities of the animal, an exceptionally rare phenomenon among bilaterians."

ScienceAdviser

Spontaneous ectopic head formation enables reversal of the body axis polarity in microscopic flatworms (open access)

Fig. 1 Morphological comparison of the wild-type asexual and double-head Stenostomum brevipharyngium

Fig. 4 Reversal of the body axis polarity in the regenerating middle zooid of the double-head worms.

Superorganism Living worm towers seen in nature for the first time. A case of collective hitchhiking in nature no matter the age of the worm

Amazing stuff! 

Can you believe there is "no role specialization among individuals in towers"!  Old worms can do it too! 😊

"When food runs out and competition heats up, nematodes assemble into living towers. They writhe and twist towards the sky with the goal of latching on to a passing animal to hitch a ride to more comfortable digs.

Scientists had hypothesised this for decades, but no one had seen these aggregations form outside of the laboratory. Now, researchers in Germany have recorded the first video footage of nematodes “towering” in the real world in decaying apples and pears. ..."

"

• First evidence of “living towers” in nature: observed in rotting apples and pears from local orchards in Konstanz, Germany
• Tower function confirmed: towers can attach to passing insects and can bridge physical gaps to disperse
• A powerful model: C. elegans are a new a tool for studying the ecology and evolution of collective dispersal

"

From the highlights and abstract:

"Highlights

• We report the first direct evidence of nematode towers occurring in nature

• Towers can serve to bridge gaps and disperse multiple individuals via phoresy

• Worms from all life stages can tower

• There is no role specialization among individuals in towers

Summary

Dispersal behavior allows organisms to find new resources under harsh conditions; collective dispersal in group-living organisms raises interesting questions about kin selection, cooperation, and social conflicts that offer an exciting window into the evolution of sociality. 

One type of collective dispersal is when individuals physically link their bodies into a super-organism and move as a group, but these phenomena are rare in nature and few empirical systems exist to enable their mechanistic dissection. Individuals of many nematode species can group together and self-assemble into a living tower of worms, which is hypothesized to be a collective dispersal structure. However, direct evidence demonstrating the occurrence and the function of towers in nature has been scarce.

We documented towering behavior under natural, semi-natural, and laboratory conditions to confirm its existence and then manipulated these towers to confirm that they can bridge gaps and respond to external stimuli to confer group dispersal by phoresy. Having established the ecological and functional relevance of nematode towers, we developed a laboratory towering assay with the model organism Caenorhabditis elegans to exploit its experimental capabilities. Our lab assay rapidly and robustly induces towering and reveals several fundamental characteristics of both the towers and the constituent individuals, which together demonstrate the high experimental potential of using our model and the ample future research avenues that it opens.

In summary, combining ecological relevance and empirical possibilities, our work sets the key foundations to establish nematode towering behavior as a powerful opportunity to elucidate the ecology, the mechanisms, and the evolution of collective dispersal."

Living worm towers seen in nature for the first time

Tower power (original news release) "Living worm towers are recorded in the wild for the first time, a rare example of collective hitchhiking in nature"

Towering behavior and collective dispersal in Caenorhabditis nematodes

A tower of fluorescent labelled C.elegans, using a pointed bristle for support

Is this not a cute drawing? One of the researchers is possibly a great fan of Leonardo da Vinci or Albrecht Dürer! 😊 You don't see such drawings very often anymore in scientific works.

Graphical abstract

Hungry and inavsive Asian hornets consume more than 1,000 species of prey in Western Europe among them honey bees and many pollinators

Amazing stuff!

"Asian hornets are formidable hunters, infamous for hanging around honeybee hives and plucking bees as they emerge. In some parts of Europe, where the hornets are invasive, beekeepers say they’ve killed up to half of their hives.  ...

Now, a study finds these ruthless hymenopterans may not be such picky eaters after all. When researchers sampled DNA from hornet nests in France, Spain, and the U.K., they found roughly 1400 species of prey. “The diet varied strongly over the seasons and between regions, showing that they are highly flexible predators ,” ... Of the 50 species most frequently consumed, 43 are known pollinators, including some of the most important ones for European crops. ..."

"... researchers tested Asian hornet samples from France, Spain, Jersey and the UK throughout the hornet’s active season.

Eaten prey included a wide range of bees, wasps, flies, beetles, butterflies, moths and spiders.

Although the European honey bee was the most common species found in the hornets – appearing in all sampled nests and almost all larvae within those nests – their diet is a lot broader.

An invasive species, Asian hornets are now found in much of western Europe. Nests are destroyed in the UK mainland each year as authorities try to keep the species out. ...

“The diet varied strongly over the seasons and between regions, showing that they are highly flexible predators. ..."

From the highlights and abstract:

"Highlights

• A highly diverse range of invertebrates are predated on by Vespa velutina

• Considerable spatiotemporal dietary variation implies a highly flexible predator

• Apis mellifera is the most frequently predated species

• The functional groups most likely at risk are wild pollinators and decomposers

Abstract

Most terrestrial invertebrates are in considerable decline, and the range expansion of the invasive hornet, Vespa velutina nigrithorax, poses an additional threat. Although now found in much of western Europe, the full extent of the hornet's predatory activity remains unexplored.

While impacts on honey bees are well-documented, evidence of a wider dietary spectrum is emerging, indicating potentially broad ecological ramifications.

Here, we conduct the first large-scale study of the diet of V. velutina, utilising deep sequencing to characterise the larval gut contents of over 1500 samples from Jersey, France, Spain, and the UK.

Our results indicate that V. velutina is a highly flexible predator, enabling its continued range expansion capacity. Analyses detected 1449 taxa, with greater prey richness in samples from southern latitudes, and considerable spatiotemporal variation in dietary composition.

Hymenoptera, Diptera, Hemiptera, Coleoptera, Lepidoptera, and Araneae were the most frequently occurring orders predated, each characterised by high taxonomic diversity. The honey bee Apis mellifera was the most abundant species, being found in all sampled nests and showing greater relative read numbers with increasing apiary density and proximity, supporting concerns for the impact of V. velutina on apiculture.

Notably, 43 of the 50 most commonly predated invertebrates were also flower visitors, including 4 common bumblebee species, indicating potentially substantial risks to wild pollinators. These data provide wide and deep evidence to support risk evaluation of this species and its potential environmental impact as it spreads across Europe."

ScienceAdviser

1,400 species found in guts of Asian hornets (original news release)

Broad ecological threats of an invasive hornet revealed through a deep sequencing approach (open access)

An Asian hornet dismembering a honey bee

Fig. 2. Overall diversity of taxa detected in the larval guts of V. velutina. The 1449 taxa across 26 orders are shown to family level for readability. Both node size and colour relate to the number of OTUs that were assigned to the displayed taxon.

Noisy soil: how sound recordings track soil health

Amazing stuff!

Want a better harvest or a nicer looking garden? Play some soil sounds!

Sounds of a happy soil!

"The team ... has found that soundscapes recorded from soil differ depending on its level of restoration. ...

So what do soils sound like?

“It’s basically clicks and crackles and pops, and little clicky sounds that these contact microphones can pick up,” ...

“It’s a reflection of all the little worms and the beetles and the ants and spiders, et cetera, moving around in the soil.” ...

These plots were at varying levels of degradation: 2 had recently been cleared, 2 had been cleared and revegetated 15 years ago, and 2 were remnant vegetation.

“Both the revegetated and reference state sites had a much more diverse soundscape than the degraded soil ...

The researchers are also trialling playing sounds to soil, with early evidence suggesting it helps to encourage better microbe growth. ..."

"Special recordings ... show this chaotic mixture of soundscapes can be a measure of the diversity of tiny living animals in the soil, which create sounds as they move and interact with their environment. ..."

From the abstract:

"Restoring and monitoring soil biodiversity has never been more important. Ecoacoustics is emerging as a promising tool to detect and monitor soil biodiversity and was recently effective in a temperate forest context. However, there is a need to investigate the efficacy of soil ecoacoustics in other ecosystems and bioregions.

Here, we applied ecoacoustics tools and indices (Acoustic Complexity Index, Bioacoustic Index, Normalised Difference Soundscape Index) to measure soil biodiversity in an Australian grassy woodland restoration chronosequence, spanning three age classes. We collected n = 240 soil acoustic samples from two cleared plots (continuously cleared through active management), two woodland plots undergoing restoration (revegetated 14–15 years ago) and two plots of remnant vegetation over 5 days in Mount Bold, South Australia. We used a below-ground sampling device and sound attenuation chamber to record soil invertebrate communities, which were also manually counted.

We found that acoustic complexity and diversity were significantly higher in revegetated and remnant plots than in cleared plots, both in-situ and in sound attenuation chambers. The acoustic complexity and diversity also significantly associated with soil invertebrate abundance and richness.

Synthesis and applications.

Our results provide new support that ecoacoustics can help monitor soil biodiversity in different forest restoration contexts, including in UK temperate and Australian grassy woodlands. This technology holds promise in addressing the global need for effective soil biodiversity monitoring methods and protecting our planet's most diverse ecosystems."

Soil’s noisy: how sound recordings track soil health

Underground ‘rave’ a sign soil is happy

Sounds of the underground reflect soil biodiversity dynamics across a grassy woodland restoration chronosequence (open access)

Fig. 1 Study sites and location (Mount Bold, South Australia).

How worms influenced evolution by increasing atmospheric oxygen

Amazing stuff!

"... The digging of prehistoric worms and other invertebrates churned up sediment along the ocean floor, exposing some minerals and burying others beneath layers of mud, silt, and sand. When scientists examined mixed sediments in the Chesapeake Bay, where conditions closely mimic those found in the early ocean, they found surprisingly high levels of pyrite—a mineral that releases oxygen when it forms but dissolves when exposed to oxygen in the water. Burrowing worms would have helped bury newly-formed pyrite while also unearthing the chemicals needed to make more of it, thereby releasing more oxygen and allowing it to build up rapidly in the atmosphere. ...
This steep increase in atmospheric oxygen kickstarted what is known as the Great Ordovician Biodiversification Event, which occurred about 480 million years ago and spawned a spectacular diversity of new animal species ..."

From the abstract:

"The early Paleozoic Era (∼540–420 Ma) was an interval of profound biogeochemical changes including increasing oxygen (O2) and the onset of bioturbation (sediment mixing by animals). It is hypothesized that incipient bioturbation caused a monotonic decrease in sedimentary burial of pyrite (FeS2), which would have slowed atmospheric O2 accumulation. However, pyrite accumulation can exhibit complex responses to dynamic, low-O2 environmental conditions. To assess pyrite burial in a potential modern analogue to early Paleozoic environments, we collected sediment cores from the Chesapeake Bay, an estuary with multiple gradients in sulfate concentration, hypoxia intensity, organic carbon flux and lability, and bioturbation. Results indicate that pyrite accumulation is maximized not under strong sulfate depletion in highly reducing sediments, but rather in sediments that occupy the mid-range of sulfate–chloride ratios. This probably occurs through efficient replenishment of pore water sulfate and/or through the generation of sulfur redox intermediates, which promote pyrite formation via the polysulfide reaction pathway. In light of these results and in contrast to earlier models, we hypothesize that mild early Paleozoic bioturbation temporarily increased pyrite burial efficiency by stimulating higher sulfate reduction rates and increasing sedimentary sulfide retention. Compiled sulfur and carbon data from a geochemical database indicate that median sulfur-carbon ratios of fine-grained marine siliciclastic rocks increased from the Ediacaran through the Ordovician, then decreased and became much less variable from the Silurian onward. Thus, the Cambrian and Ordovician Periods may constitute a distinct interval of the Proterozoic-Phanerozoic transition in which bioturbation temporarily accelerated O2 buildup. This transition probably ended in the Silurian, when pO2 rose to sufficient levels to homogenize sedimentary carbon–sulfur cycling."

ScienceAdvisor

Trends in estuarine pyrite formation point to an alternative model for Paleozoic pyrite burial (open access)

Do octopuses dream? Brain recordings provide the first clues

Amazing stuff! Will I be dreaming of octopuses tonight? 😊

Do Invertebrates Have Emotions?

Recommendable! This is a comprehensive overview article. Why should emotions be confined to vertebrates? How necessary is a nervous system or are there alternatives?

"... Decades ago, scientists and lawmakers had all but reached a consensus that invertebrates could not feel pain, let alone other emotions like joy or fear. Recently, however, evidence is mounting that invertebrates are more than just reflexive beings. Experiments in bees, crabs, and octopuses show that some invertebrate animals can learn from painful experiences, have positive and negative emotion-like states, and might even experience a range of other emotions beyond pain and pleasure. ...
Still, many scientists remain extremely skeptical, and the question of whether invertebrates can experience emotions is hotly debated. ..."

From the abstract:

"If the UK joins a handful of other nations to recognize the sentience of invertebrates, such as cephalopod mollusks and decapod crustaceans, by, for example, prohibiting the boiling of live lobsters, this will be based on evidence that emotions and felt experiences (i.e., sentience) are not limited to animals close to humans, such as the mammals. This topic has been heavily debated in both affective neuroscience (how to define an emotion?) and philosophy (what is the moral relevance of animal experiences?), but a consensus on the criteria for and implications of recognizing animal sentience seems to be emerging"

Do Invertebrates Have Emotions? | The Scientist Magazine® And how do scientists go about answering that question?

The question of animal emotions (no public access) Do animals, including invertebrates, have felt emotions and does this morally matter?